The current (7th) International Union Against Cancer (UICC) pN staging system is based on the number of positive lymph nodes but does not take into consideration the characteristics of the metastatic lymph nodes itself. In particular, it has been suggested that tumour penetration beyond the lymph node capsule in metastatic lymph nodes, which is also called extracapsular lymph node involvement, has a prognostic impact. The aim of the current study was to assess the prognostic value of extracapsular (EC) and intracapsular (IC) lymph node involvement (LNI) in adenocarcinoma of the oesophagus and gastro-oesophageal junction (GOJ) and to assess its potential impact on the 7th edition of the UICC TNM manual.METHODS:
From 2000 to 2010, all consecutive adenocarcinoma patients with primary R0-resection (n = 499) were prospectively included for analysis. The number of resected lymph nodes, number of positive lymph nodes and number of EC-LNI/IC-LNI were determined. Extracapsular spread was defined as infiltration of cancer cells beyond the capsule of the positive lymph node.RESULTS:
Two hundred and eighteen (43%) patients had positive lymph nodes. Cancer-specific 5-year survival in lymph node-positive patients was significantly (P < 0.0001) worse compared with lymph node-negative patients, being 88.3 vs 28.7%, respectively. In 128 (58.7%) cases EC-LNI was detected. EC-LNI showed significantly worse cancer-specific 5-year survival compared with IC-LNI, 19.6 vs 44.0% (P < 0.0001). In the pN1 category (1 or 2 positive LN's—UICC stages IIB and IIIA), this was 30.4% vs 58%; (P = 0.029). In higher pN categories, this effect was no longer noticed. Integrating these findings into an adapted TNM classification resulted in improved homogeneity, monotonicity of gradients and discriminatory ability indicating an improved performance of the staging system.CONCLUSIONS:
EC-LNI is associated with worse survival compared with IC-LNI. EC-LNI patients show survival rates that are more closely associated with the current TNM stage IIIB, while IC-LNI patients have a survival more similar to TNM stage IIB. Incorporating the EC-IC factor in the TNM classification results in an increased performance of the TNM model. Further confirmation from other centres is required within the context of future adaptations of the UICC/AJCC (American Joint Committee on Cancer) staging system for oesophageal cancer.